21521244544 has 32 divisors (see below), whose sum is σ = 42893042040. Its totient is φ = 10755932160.

The previous prime is 21521244517. The next prime is 21521244553. The reversal of 21521244544 is 44544212512.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 268032 + ... + 338944.

Almost surely, 2^21521244544 is an apocalyptic number.

It is an amenable number.

21521244544 is a deficient number, since it is larger than the sum of its proper divisors (21371797496).

21521244544 is an equidigital number, since it uses as much as digits as its factorization.

21521244544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73298 (or 73286 counting only the distinct ones).

The product of its digits is 51200, while the sum is 34.

The spelling of 21521244544 in words is "twenty-one billion, five hundred twenty-one million, two hundred forty-four thousand, five hundred forty-four".